Spatial contrast sensitivity was used to assess losses or changes in overall visual resolution in patients having a variety of toxic, inflammatory, degenerative, or congenital retinal and neuro- ophthalmological disorders of the visual system. A criterion-free forced-choice physchophysical procedure was used, since this method was previously shown to minimize false positive or false negative diagnosis at initial test and to minimize spurious changes in sensitivity with repeated testing. Contrast sensitivity testing, while requiring more patient testing time, continued to be superior to conventional acuity measurements for the detection of early losses and for monitoring changes in visual resolution in patients undergoing treatment. Age-referenced normative data make it possible to distinguish contrast sensitivity loss due to ocular disorder from that expected on the basis of normal aging. A retinal image stabilization system is under construction. This system is intended to permit focal electroretinography and high resolution microperimetry in small, localized regions of a patient's retina.